Mining machine having independent means to rotate and oscillate cutters



March 14, 1967 E. M ARENTZEN 3,309,145

MINING MACHINE HAVING INDEPENDENT MEANS TO ROTATE AND OSCILLATE CUTTERS Filed March 8, 1965 5 Sheets-Sheet l March 14, 1%? E. M. ARENTZEN BSWJAS MINING MACHINE HAVING INDEPENDENT MEANS TO ROTA'IE AND OSCILLATE CUTTERS Filed March 8, 1965 5 Sheets-Sheet 2 INVENTOR. B El/VAI? M. ARENTZ'EN Attorneys M, 1%? E. M. ARENTZEN wwma MINING MACHINE HAVING INDEPENDENT MEANS TO ROTATE AND OSCILLATE CUTTERS Filed March a, 1965 5 Sheets-Sheet s' M W Attorneys March 14, 1967 E. M. ARENTZEN 3 3%,M5

MINING MACHINE HAVING INDEPENDENT MEANS TO ROTATE AND OSCILLATE CUTTERS Filed March 8, 1965 5 Sheets-Sheet 4 "7' 17 ill/I117 II/rl R \\\\\\\\l l l/V VE/VTOP. E/IVAI? M. ARE/VTZE/V Arrorneyfi r h 1%? M. ARENTZEN swam MINING MACHINE HAVING INDEPENDENT MEANS TO ROTATE AND OSCILLATE CUTTERS Filed March 8, 1965 5 Sheets-Sheet 5 A t for/rays MINING MACHINE HAVING INDEPEND- ENT MEANS T ROTATE AND ()SCIL- LATE CUTTERS Einar M. Arentzen, Charleroi, Pa, assignor to Lee-Norse (Iompany, Charleroi, Pa, a corporation of Delaware Filed Mar. 8, 1965, Ser. No. 437,825 11 filaiins. ((Il. 299-71) This invention relates to mining machines, and more particularly mining machines of the type in which revolving cutter heads are mounted at the ends of oscillating arms which in turn are carried on a boom which may be raised and lowered. The present invention pertains specifically to an improvement in machines as shown in Arentzen Patent No. 2,695,164, granted Nov. 23, 1954, and in my copending application Serial No. 387,583, filed August 5, 1964.

In the mining machine disclosed in said patent there i a boom which may be swung in a vertical arc, and on this boom there are two arms which oscillate during operation of the machine toward and away from each other in isochronism. Each arm has a cutter head at its outer end that rotates about a horizontal axis as the arms move back and forth, and also while the boo-m may be moving down or up. On each side of the machine there is a drive motor which rotates a shaft extending lengthwise of each arm. Gearing at the end of this shaft rotate the cutter, while a worm gear intermediate the ends of the shaft engages a worm gear that rotates a crank. A link extends from the crank on each arm to a fixed common point of anchorage on the boom. The arrangement is such that as each motor rotates its shaft, it rotates the cutter head and also rotates the crank. The links, anchored at one end to the boom, cause the arms to move toward and away from each other as the cutters revolve, and the two drive motor are mechanically connected to assure that the arms approach and recede from each other in isochronism.

This has been a highly satisfactory arrangement for use in many mines, but in some conditions it is not sutficiently flexible to meet some requirements, and because of the rigidity of the mechanical drive, mechanical shock sometimes resulted in the breaking of crank pins, or breakage in the worm drive. This breakage becomes increasingly prevalent as the power of the driving motors is increased. On the other hand, a mechanical crank operation is highly desirable since it is inherent in a crank operation that the speed of travel of the arms decelerates as the crank and link approach a position where they are in line or on center and accelerates as the crank moves away from over center position, so that the arms slow down gradually as they approach the inner and outer limits of their arcuate travel, and then as their direction of travel reversed, pick up speed smoothly and evenly.

The present invention has for its object to provide a crank type of operation with the desirable qualities above described in a drive that will yield or stall under excessive shock or stress, thereby eliminating the stripping of gears or crank pin breakage due to some abnormal condition.

Additionally the invention provides a mechanism that will not only yield under adverse conditions before breaking stresses are imposed on the parts, but which may be reversed at any point in its cycle to back off from the impediment. For example, if the arms are moving toward each other and a large mass of material such as rock or coal should be encountered that would normally overstress the mechanism, the operator may immediately reverse the motion of the arms, whereas this was not previously possible.

A still further object is to provide a machine in which "atent ()filic Patented Mar. 14, 1967 the cutters may be revolved without oscillating the arms.

These and other objects and advantages are secured by the present invention wherein the links for moving the arms have their end-s pivotally fixed to the arms with the crank means which comprise eccentrics on a centrally positioned power-driven shaft which rotates the eccentrics to move the links and thereby oscillate the cutter arms. The motor drive for rotating the shaft is a hydraulic means separate from the cutter rotating drive, and this motor means can be harmlessly stopped while the cutters can be driven, if desired. Since the drive motor means for oscillating the arms is mechanically separate from the motors which rotate the cutter wheels, the arms are oscillated together without the mechanical connection required in my said patent for synchronizing the two cutter driving motors. Additionally this mechanism eliminates certain disadvantages particularly in heavy machines involved in the use of hydraulic cylinders as disclosed in my said application Ser. No. 387,583 while retaining the advantages of that construction.

The invention may be more fully understood by reference to the accompanying drawings which illustrate an embodiment of my invention, and in which:

FIG. 1 is a plan view of a mining machine embodying this invention with the deck cover over the oscillating arms removed and with only a fragment of the conveyor being shown;

FIG. 2 is a side elevation of the machine shown in FIG. 1, and in dotted lines, the boom being indicated in raised position;

FIG. 3 is a detail plan view of the mechanism for oscillating the cutter heads, part of the cover of the gear housing being broken away, and part of one of the drive shaft connnections being shown in section;

FIG. 4 is a longitudinal section in the plane of line IV-IV of FIG. 3, the view being on a larger scale than FIG. 3, and in this view the cover of the gear housing is shown in place and is in section;

FIG. 5 is a transverse vertical section in the plane of line V-V of FIG. 3 with portions of the links for oscillating the cutter arms being shown in elevation and partly in section;

FIG. 6 is a fragmentary detail view in substantially the plane of line VI-VI of FIG. 4, but on a smaller scale showing the lubricant pump and the operating cam therefor;

FIG. 7 is a horizontal plan view in substantially the plane of line VII VII of FIG. 5; and

FIG. 8 is a schematic diagram of the fluid pressure circuits employed in the driving of the fluid pressure motors and in the lubricating of certain parts.

Referring to the drawings in which corresponding reference numerals designate corresponding parts, FIGS. 1 and 2 show the general organization of the machine, and in FIG. 1 the deck plate covering the oscillating cutter arms is removed to more clearly show the construction.

The machine which is mobile, has a main body section 2 mounted on crawlers or tractor treads 3 driven by hydraulic motors schematically indicated at 4. At the forward end of the machine there is a boom structure which is substantially the full width of the machine and which is designated generally as 5. It is arranged to be moved up and down in a vertical arc, hydraulic cylinders 6 at each side of the body of the machine with piston rods 7 connected at 8 to the boom being provided for effecting this vertical movement. The pivotal support for the boom is low down at each side of the body at 9.

The machine is provided at its forward end with a downwardly-sloping gathering apron 10 over which gathering arms 11 sweep coal that has been loosened onto the forward end of a longitudinally-extending conveyor pan 12, this conveyor having an endless conveyor chain 13 with flights 13a of a type commonly used in mining machines and by which coal is carried from the forward end of the machine to an overhanging discharge terminal 14 at the rear. This conveyor per se forms no part of the instant invention, and the general arrangement is more fully shown and described in my prior Patents 2,695,164 and 2,766,871.

The boom supports two similar cutter arms 15. At the front of the boom there is a cross frame 16 on which are two curved guide rails 17 in the form of a rearwardlyturned ledge. Each cutter arm 15 has a plate 18 fixed thereto that rests on this ledge and slidably supports the front end of the arm on the rail so that the arm is hung from and is slidable laterally in an arc on the rail. At the rear end of each arm there is a universal joint 19 which is on the end of a shaft 2% that extends forwardly through the arm. On the outer end of each arm there is a cutter head comprising a gear box 21 and a worm on the forward end of the shaft 20 meshes with a worm gear (not shown) through which a transverse cutter shaft 22 is driven, the details of this construction being unimportant to the present invention and being shown in detail in my application Ser. No. 387,583. Each end of the shaft 22 projects beyond the end of the gear box and is provided with a cutter wheel 23 having cutters 23a arranged about its periphery, generally as shown in more detail in Patent 2,695,154. The arrangement is such that when shaft 22 is rotated, the cutter wheels 23 will be revolved.

Each shaft 20 has the universal joint 19 at its inner end contained within a gear box 24a. On each side of the machine is a mine type electric motor 25. Each motor operates through gearing (not shown) in the gear box 24 to drive one of the shafts 20 and to also drive a high pressure fluid pump 27. It is with these pumps and the parts described in the subsequent description that the present invention is more directly concerned.

Mounted on the boom midway between the two oscillatory arms 15 there is a gear box or housing 30, the general location of which is shown in FIG. 1, and which is shown in greater detail in FIGS. 3, 4, and 7. There is a vertical shaft 31 in this housing that is splined throughout the greater portion of its length. Its lower end is received in a ball bearing 32. Keyed to the upper end of this shaft is a worm gear wheel 33 having a hub portion 33a and a separate gear ring 33b bolted thereto. The hub of the gear wheel is supported in upper and lower cone bearings 34 and 35. Enclosure 36 forming part of the housing encloses this gear wheel and its hearings in order to exclude dust and retain lubricant. A removable cover 37 is shown over this gear wheel.

Also keyed to the shaft 31 by means of the splines on the shaft are upper and lower eccentrics 4E) and 41 which are positioned approximately 90 out of phase. Encircling the upper eccentric 40 is a split collar 42 having one part 4211. formed on the end of a link 43, and the other part 42b is bolted to 42a by bolts 44. Surrounding the lower eccentric 41 is a similar split collar 45 having one portion 45a integral with a link 46 and having its other half section 45b bolted thereto by bolts 47.

The housing 30, as best seen in FIG. 7 has wide openings therethrough, and the link 43 extends laterally to the left as viewed in this figure outwardly through the housing and the link 46 similarly extends out through the housing to the right, or vice versa, so that these links diverge forwardly at the minimum angle shown in full lines of about 90, and as the vertical shaft 31 is rotated this angle increases and the outer ends of the arms move outwardly in substantially equal amounts but in opposite directions. By reference to FIG. 5, it will be noted that the mid portion of each link has an opposite vertical offset so that their outer terminals are at about the same horizontal level.

The outer ends of the respective links are pivotally attached at St to the respective arms 15 toward which they extend, the pivotal connection for one of these links being shown in section in H6. 5, the construction including a spherical sleeve as shown in this figure to prevent any binding.

For driving the worm wheel there are two similar hydraulic motors 55, each having a shaft 56 with a worm 57 thereon, the two worms 57 being located at diametrically opposite sides of the gear wheel and meshing with it, the two worms being of reverse pitch so that with both motors turning their shafts in the same direction, they both operate to turn the gear wheel 33 with its shaft 31. When these motors are operating, the rotation of the shaft 31 rotates the two eccentrics and 41. This causes the links 43 and 26 to thrust the arms 15 away from each other and then draw them together, moving them toward and away from each other and toward and away from the longitudinal axis of the machine at equal speeds and in synchronism.

The fluid pressure system for these two hydraulic motors is shown schematically in FIG. 8. The letter R wherever it appears in this diagram designates a common reservoir for the hydnaulic fluid, which is generally oil. A low pressure pump 64) draws oil from the reservoir, forces it through a cooler 61 into a filter 62 which has an outlet pipe 63. One branch 64 leads to the intake of one of the high pressure pumps 27 above referred to, and a second branch 65 leads to the intake of the other high pressure pump 27 on the opposite side of the machine. The puipose of pump 6! is to assure an adequate supply of liquid to the high pressure pumps at all times. Excess liquid isbypassed through a pressure relief valve 66 to an oil return line 67 and filter 68 back to the reservoir R.

The outlet of the first-mentioned high pressure pump 27 is discharged through pipe 69 to a distributor 70, and the other high pressure pump 27 discharges its high pressure oil into pipe 71 that leads also to the distributor,

. where the flow from both pumps join.

When the machine is operating, the main stream of high pressure oil flows out of the distributor through the pipes 72 and 73, here shown as being located diagonally opposite the location of the pipes 69 and 71, pipes 71 and 73 leading to the inlet sides of the respective hydraulic motors 55. The outlets of these motors is into pipes 74 and 75 back to the distributor 70. From the distributor the discharge oil from the motors is carried through pipe 74-75 into pipe 67 and thence to the reser voir. Leakage into the motor housing where it might impair the power of the motors is carried away through the connections 76 indicated in dotted lines to the discharge pipe 75.

There is an on-and-off valve positioned at the operators station, and it is indicated at 77. When it is open, the high pressure oil is led directiy from, the distributor through pipe 78 and through valve 77 directly back to the reservoir, thereby shunting the flow away from the motors 55 so that they will not operate. Operation of valve 77 to closed position closes this bypass pipe 78 to force the liquid through the motors 55.

The distributor includes :a conventional flow-reversing valve schematically indicated by the crossed passages in the diagram at 80, and which is normally spring-biased to direct high pressure oil into pipes 72 and 73. By operation of this valve the high pressure fluid may be directed into pipes 74 and 75, and 72 and 73 then become exhaust lines. This valve and its operating mechanism is per se known and for this reason is not shown in detail. To effect reversal a spring-biased valve is indicated at 80a near the machine operators station (as S in FIG. 1), and it is normally in the position indicated where any high pressure fluid in line 861) may drain back to the reservoir so that the spring in the valve 80 is effective to keep this valve in normal position. To effect reversal, the valve operator S00 is pushed in so that high pressure oil from pipe 86d flows into pipe 8% to overcome the biasing force of the spring and effect a reversal of flow to the motors 55 as above described until operator 890 of the valve 80a is released. The distributor also has a pressure relief valve built into it and which is schematically indicated at 80 so that if the motors 55 are overloaded, the pressure fluid may flow out the pipe 74. This is also a usual arrangement in a fluid motor driving system, and is shown in greater detail in my application Ser. No. 387,583 above referred to.

Some of the oil is used for forced lubrication. It is led from the distributor through pipe 81 to a metering pump 82. This is a plunger type piston pump that is operated by a cam on the gear Wheel 33 (see FIGS. 5 and 6). This cam 83 is bolted onto the hub of the gear wheel and with each rotation of the gear wheel it strikes a plunger 84, pushing a measured amount Olf oil out of the pump and the high pressure fluid at the pump inlet biases the plunger to move in the opposite direction. The usual pump valves are not shown. The flow of oil from this plunger pump is out pipe 85 into a lubricant distributor 86 from which lead several lubricant lines such as 87 and 83 for lubricating the eccentrics and the pivots 55a. Another pipe 89 leads from the pump 82 to a pressure relief valve 89a for passing lubricant to the reservoir.

In the operation of the machine the electric motors 25 drive the cutter wheels and as they rotate the hydraulic motors operate the links 43 and 46 to move the cutter heads back and forth across the working face of the mine, ripping and tearing the coal out of the seam. Usually the boom is elevated to the roof and the cutters are sumped in and then the boom is lowered with the cutters rotating and the cutter heads moving back and forth. There is preferably a removable deck plate 95 on the boom, over the arms, to prevent the coal or mine roof from falling down onto the links 43 and 46 or the various mechanisms carried by the boom under the deck.

The motors 25 are mechanically independent of each other, but each contributes the same amount of power to the arm oscillating mechanism, but each drives one set of cutter independently of the other. Preferably about 20% of the power from the motor 25 is required for the pumps 27 and the remainder is applied to rotating the cutters. The rotation of either set of cutter wheels may be stopped by stopping one motor, in which case the other motor will operate its cutter wheels and also oscillate the two cutter arms. If one motor 25 fails, the operator is immediately apprised of it by the stopping of one set of cutter wheels. The cutter wheels of each head may operate without oscillating the arms by merely opening valve 77.

There are two hydraulic motors 55 for oscillating the cutter arms, because this distributes the thrust exerted against the worm gears and teeth on the gear wheel 33 so that this gear wheel need not be as large and heavy as would be required with one hydraulic driving motor. The forces are also more symmetrically located about the shaft 31.

A most important advantage is that by moving the links 43 and 46 through rotating eccentrics, the oscillation of each arm approaches zero speed gradually at each limit of travel of the arms and then, as the eccentrics move over center, the movement of the arms reverses and the speed accelerates and then decelerates gradually as the opposite limit of travel is approached. This eliminates the violent abrupt jarring that occurs with some types of drives, such as where hydraulic cylinders are used for oscillating the arms.

Another advantage is that if the cutters encounter some inclusion in the coal being mined, the hydraulic motors will slow down or stall while the cutter wheels can rotate at their usual speed to cut away the hard inclusion, and the stalling of the oscillation of the arms imposes no such shock in the linkages such as will bend or shear pivot pins. Also, if some object prevents the arms from moving together toward each other, the reversing of the motors 55 will release the object caught between the arms, whereupon the obstruction may drop away or be cleared away manually, whereas in no other coal miner of this character can the movement of the arms be reversed while the cutters rotate always in the direction in which they are intended to operate.

In a related application executed this same day, Ser. No. 437,824, filed Mar. 8, 1965, I have shown another embodiment of the basic arrangement herein disclosed, but wherein the links are moved by an electric motor.

While I have shown and described one embodiment of my invention and a preferred manner of constructing the same, it will be understood that the mechanism may be modified by those skilled in the art within the contemplation of my invention and within the scope of the appended claims.

I claim:

1. In a mining machine of the type having a boom with a pair of arms thereon supported for arcuate swinging movement laterally toward and away from each other and the fore-and-aft center line of the boom, each arm having a cutter head at the outer end thereof with cutter wheels thereon and a separate electric motor on the machine for driving the cutter wheels of the cutter head, each motor being operatively connected with the cutter wheels of only one head, the invention comprising a mechanism for oscillating the arms synchronously toward and away from each other, said mechanism comprising:

a shaft located on the boom between the arms,

a pair of links each having one end attached to one of said arms intermediate the length of the arms and extending toward said shaft,

eccentric means on the shaft,

means on each link engaging said eccentric means and arranged to move the links simultaneously in opposite directions when the eccentric means is rotated,

and motor means mechanically separate :from the said electric motors which rotate the cutter wheels operatively connected with said shaft for rotating the same.

2. The invention defined in claim 1 wherein the motor means for rotating the shaft is reversible.

3. The invention defined in claim 1 wherein the motor means comprises a hydraulic motor, a high pressure pump for supplying high pressure liquid to the motor and piping connecting the output of the pump with the motor, and means for driving the pump.

4. The invention defined in claim 3 wherein the piping includes a valve controlled bypass for diverting the flow of high pressure liquid away from the motor means whereby the pump may continue to operate while the motor means is stopped.

5. In a mining machine of the type having a boom with a pair of arms thereon supported for arcuate swinging movement laterally toward and away from each other and the fore-and-aft center line of the boom, each arm having a cutter head at the outer end thereof with cutter wheels thereon and a separate electric motor on the machine for driving the cutter wheels of each cutter head, each motor being operatively connected with the cutter wheels of only one head, the invention comprising a mechanism for oscillating the arms synchronously toward and away from each other, said mechanism comprising:

a shaft located on the boom between the arms,

a pair of links each having one end pivotally attached to one of said arms intermediate the length of the arms and extending toward the shaft,

eccentric means on the shaft,

means on each link engaging said eccentric means and arranged to move the links simultaneously in opposite directions when the eccentric is rotated,

hydraulic motor means for driving said shaft,

means for transmitting power from the hydraulic motor means to the shaft,

2. separate high pressure pump having an intake and J an outlet operatively coupled to each of said electric motors, and

means for transmitting high pressure liquid from both of said pumps to the hydraulic motor means for supplying operating liquid under pressure thereto.

6. The invention defined in claim in which the hydraulic motor means comprises two separate hydraulic motors, and wherein there is a worm driven by each motor, and

a worm wheel on said shaft engaged with both of said worms whereby the power for rotating the shaft is divided between the two motors and the Worms which they drive.

7. The invention defined in claim 6 in which the output of the two pumps is combined and thereafter divided into separate pipes leading to the separate hydraulic motors.

8. The invention defined in claim 6 in which the output of the two pumps is combined and thereafter divided into separate pipes leading to the separate hydraulic motors, there being a liquid reservoir and a pipe system for discharging liquid from the hydraulic motors to the reservoir, and means for transferring liquid from the reservoir to the intakes of the respective high pressure pumps.

9. The invention defined in claim 6 in which the output of the two pumps is combined and thereafter divided into separate pipes leading to the separate hydraulic motors, there being a liquid reservoir and a pipe system for discharging liquid from the hydraulic motors to the reservoir, means :for transferring liquid from the reservoir to the intakes of the respective high pressure pumps, and a manually operable valve for selectively bypassing the high pressure liquid from both pumps around the hydraulic motors for stopping the hydraulic motors while the pumps continue to operate, whereby the electric motors may continue to drive their cutters while the arms remain stationary on thetboom.

10. In a mining machine of the ripper type having a boom with two arcuately movable arms mounted thereon for arcuate movement toward and away from each other, each arm having a power-driven cutter head extending forwardly from the boom, the invention comprising means for oscillating said arms comprising a housing mounted on the boom,

a vertical shaft in the housing,

means for driving the vertical shaft,

a pair of eccentric disks on said shaft and fixed thereto,

a separate collar encircling each disk within which the disk is rotatably fitted, each collar being at one end of a link, one link having its opposite end pivotally attached to one of the arms, the disks being so disposed with relation to each other as to effect equal and opposite oscillatory movement to the arms whereby they move toward and away from each other in substantial unison.

11. The invention defined in claim 10 in which the driving means for the shaft comprises at least one hydraulic motor, and means for supplying liquid under pressure to said motor for driving it.

References Cited by the Examiner UNITED STATES PATENTS 2,695,164 11/1954 Arentzen 299-71 3,052,454 9/1962 Sibley 299--71 3,157,437 11/1964 Gonski 299-71 3,170,732 2/1965 Hlinsky 29964 X ERNEST R. PURSER, Primary Examiner. 

10. IN A MINING MACHINE OF THE RIPPER TYPE HAVING A BOOM WITH TWO ARCUATELY MOVABLE ARMS MOUNTED THEREON FOR ARCUATE MOVEMENT TOWARD AND AWAY FROM EACH OTHER, EACH ARM HAVING A POWER-DRIVEN CUTTER HEAD EXTENDING FORWARDLY FROM THE BOOM, THE INVENTION COMPRISING MEANS FOR OSCILLATING SAID ARMS COMPRISING A HOUSING MOUNTED ON THE BOOM, A VERTICAL SHAFT IN THE HOUSING, MEANS FOR DRIVING THE VERTICAL SHAFT, A PAIR OF ECCENTRIC DISKS ON SAID SHAFT AND FIXED THERETO, A SEPARATE COLLAR ENCIRCLING EACH DISK WITHIN WHICH THE DISK IS ROTATABLY FITTED, EACH COLLAR BEING AT ONE END OF A LINK, ONE LINK HAVING ITS OPPOSITE END PIVOTALLY ATTACHED TO ONE OF THE ARMS, THE DISKS BEING SO DISPOSED WITH RELATION TO EACH OTHER AS TO EFFECT EQUAL AND OPPOSITE OSCILLATORY MOVEMENT TO THE ARMS WHEREBY THEY MOVE TOWARD AND AWAY FROM EACH OTHER IN SUBSTANTIAL UNISON. 